Comparison of the ability of bread versus bread plus meat to treat and prevent subsequent hypoglycemia in patients with insulin-dependent diabetes mellitus.

We sought to determine whether treatment of hypoglycemia with a snack containing both protein and carbohydrate results in more prolonged protection against subsequent hypoglycemia than ingestion of carbohydrate alone. We studied six insulin-dependent diabetic subjects on two occasions. On both occasions subjects received a variable overnight insulin infusion to achieve euglycemia followed by a constant insulin infusion (approximately 0.5 mU x kg(-1) x min(-1)) designed to produce hypoglycemia. When glucose reached 50 mg/dL, subjects were fed a snack consisting of either bread (approximately 85 kcal) or bread plus meat (approximately 205 kcal). Both contained 15 g of carbohydrate. The insulin infusion was continued for the next 3 h or until glucose again fell to 50 mg/dL. Although bread plus meat resulted in a more marked rise (P < 0.05) in glucagon than did bread alone, neither the post treatment peak glucose concentration (73 +/- 4 vs. 70 +/- 6 mg/dL) nor the subsequent rate of fall of glucose (0.42 +/- 0.10 us. -0.35 +/- 0.07 mg/dL/min) differed. The present study shows that the rate of redevelopment of hypoglycemia does not differ after eating bread or bread plus meat. Therefore treatment of hypoglycemia with a protein-enriched snack merely adds calories rather prolonged protection against subsequent hypoglycemia.

Metabolism of triacetin-derived acetate in dogs.

Triacetin is a water-soluble triglyceride that may have a role as a parenteral nutrient. In the present study triacetin was administered intravenously to mongrel dogs (n = 10) 2 wk after surgical placement of blood-sampling catheters in the aorta and in the portal, hepatic, renal, and femoral veins. [1-14C]Acetate was infused to allow quantification of organ uptake of acetate as well as systemic turnover and oxidation. Systemic acetate turnover accounted for approximately 70% of triacetin-derived acetate, assuming complete hydrolysis of the triglyceride. Approximately 80% of systemic acetate uptake was rapidly oxidized. Significant acetate uptake was demonstrated in all tissues (liver, 559 +/- 68; intestine, 342 +/- 23; hindlimb, 89 +/- 7; and kidney, 330 +/- 37 mumol/min). In conclusion, during intravenous administration in dogs, the majority of infused triacetin undergoes intravascular hydrolysis, and the majority of the resulting acetate is oxidized. Thus, energy in the form of short-chain fatty acids can be delivered to a resting gut via intravenous infusion of a short-chain triglyceride.

Beyond 1 year after liver transplantation.

We retrospectively reviewed the long-term results in 46 patients who survived at least 1 year after liver transplantation. Only one death has occurred, and one patient has required retransplantation. Biochemical liver function tests showed median values in the normal range, except for mild elevation of serum gamma-glutamyltransferase. In patients with primary biliary cirrhosis, these test results were completely normal. A liver biopsy 1 year after transplantation disclosed normal histologic findings in 31 patients (67%). The other patients had either transient (acute rejection) or stable (chronic rejection) abnormalities, except for two patients with progressive graft dysfunction attributable to chronic rejection. A clinically significant vascular anastomotic abnormality was noted in one patient who had hepatic artery thrombosis. Late bile duct complications occurred in 15% of patients, all of whom had a satisfactory outcome after surgical or radiologic intervention. Cyclosporine-related nephrotoxicity and hypertension each occurred in 67% of patients; however, conversion to a low-dose cyclosporine-azathioprine regimen yielded stabilization of renal function after the first postoperative year, and hypertension has been easily controlled medically. Diabetes necessitating insulin treatment developed in three patients. The body weight of the study patients had increased by a median of 6.5 kg at 1 year but stabilized thereafter. Subjective well-being and satisfaction with life were reported by 91% of the patients. Of the 46 patients, 26 were employed, 16 were homemakers, and only 4 did not work, 2 because of transplant-related medical problems. Thus, we conclude that liver transplantation rehabilitates patients with end-stage liver disease and enhances their quality of life.

Superior vena caval obstruction in patients with gut failure receiving home parenteral nutrition.

Clinical suspicion and venographic conformation were used to diagnose 15 cases of superior vena caval obstruction (SVCO) in 107 home parenteral nutrition (HPN) patients over 379 cumulative years of HPN (3.9 cases/100 patient-years). Patients with SVCO had been on HPN a mean of 51.5 months and had used 6.2 (range 1-50) central catheters, including short- and long-term, before SVCO was diagnosed. The frequency of inflammatory bowel disease (IBD) with SVCO was approximately the same as that in our general HPN population. Positive blood cultures were present immediately preceding the diagnosis of SVCO in 40% (six of 15) of cases. Atypical line placements were noted in two cases. The most common management strategies employed were conversion to enteral feedings in five patients and placement of a new catheter directly into the right atrium by thoracotomy in another five patients. Two of the five with right atrial catheters experienced a postpericardiotomy syndrome (fever, pericardial rub, and pulmonary infiltrates) that responded promptly to indomethacin. The most significant long-term sequela of SVCO was the need for a left jugular vein to right atrial appendage bypass in one patient with chronic venous congestion from her SVCO. Once the SVCO is confirmed, systemic heparinization provides immediate antithrombotic effect and minimizes the risk of pulmonary embolism. The use of streptokinase may result in rapid thrombolysis.

Systemic and regional acetate kinetics in dogs.

Little is known about the sites of production and uptake of acetate in nonruminants. We placed blood sampling catheters in the femoral artery and in the femoral, portal, hepatic, and renal veins of mongrel dogs (n = 11). The animals were studied in the conscious state 2 wk later during a primed continuous infusion of [1-14C]acetate. Systemic acetate turnover, oxidation, and clearance were determined, as well as regional uptake and release, by measuring 14CO2 excretion as well as plasma concentration and specific activity at the five sampling sites. Results showed systemic acetate turnover was 8.8 +/- 1.9 mumol.kg-1.min-1, approximating 5% of energy expenditure in dogs. Simultaneous uptake and release of acetate was demonstrated in intestine, liver, kidney, and hindlimb. The intestine was the greatest contributor to acetate production, whereas the liver was the most important site of uptake. Plasma acetate oxidation was 77 +/- 4% of turnover. Both systemic clearance (129 +/- 22 ml.kg-1.min-1) and tissue fractional extraction (68-85%) were many times greater than values reported for glucose, free fatty acids, lactate, or amino acids. In conclusion, most tissues simultaneously take up and release acetate in dogs. This may represent a mechanism for interorgan transport of energy, especially under conditions of caloric deprivation.